Process for suspending glass plates



Hum 24, 194%. G, P. DESPRET 2,247,289

PROCESS FOR SUSPENDING GLASS PLATES Original Filed March 23, 1.936 2Sheets-Sheet l attorney June 24, 1941. e. P. DESPRET PROCESS FORSUSPENDING GLASS PLATES Original Filed March 23, 1936 2 Sheets-Sheet 2Patented June 24, 1941 PROCESS FOR SUSPENDING GLASS PLATES Georges PaulDespret, Paris, France, assignor to The American Securit Company,Washington, D. 0., a corporation of Delaware Original application March23, 1936, Serial No. 70,479, now Patent No. 2,156,011, dated April 25,1939. Divided and this application October 13, 1928, Serial No. 234,832.In France March 2d,

2 Claims.

During the tempering step of glass plates, sheets or other similarproducts the sheets are generally suspended at their upper part bygrippers of the so-called "frog leg" type, the advantage of this methodof suspension consisting in that a very small zone or surface of thesheet is engaged.

The grippers themselves are attached to a support which is generallymovable, for example a horizontal bar.

The sheets thus suspended are carried into a heating furnace of anysuitable construction in which they are carried to a temperature nearthe softening point. When this temperature has been attained the sheetsare withdrawn from the furnace and carried into a cooling apparatuswhere they are suddenly cooled. In this manner the sheets pass into theso-called tempered state, through which they are given new properties,such as resistance to fracture, to heat, etc.

During the operation the glass sheets suspended as before described maybecome deformed through the action of the heat, particularly if thesheets are of great dimensions.

The present invention relates to a suspension" apparatus for glassplates or sheets, panes or similar products, applicable particularly inthe tempering operation, for the purpose of preventthe gripper supportabove, in raising the suspended sheet after the heating, the grippersare prevented from closing suddenly, "through the action of inertia, dueto the massof the sheet, and sharply impressing their points into theglass, or sheets of other material and thus create deformation in thevicinity of these points. The resilient suspension thus precludes suchlocal defamation.

The suspension device is completed preferably by a frame or chassishaving rigid sides, intended to encompass temporarily one or more sidesof the suspended plate, this frame comprising stop members mountedoppositely in pairs, between which the corresponding edge of thesuspended plate engages.

These stops prevent deformation of the sheet during their heating. Asknown, the heat being concentrated at the centre of the furnace, theglass plates, sheets, etc. have a tendency to deform by bulging ortorsion. The frame stops,

thus hold the sheet perfectly flat.

This application is a division of my prior filed application Serial No.70,479, filed March 23, 1936, Patent No. 2,156,011, issued April 25,1939.

Other features will be apparent from the following description.

On the accompanying drawings, given by way of example:

Figure 1 is a front elevation of the assembled improved suspensiondevice.

Figure 2 is a profile.

Figure 3 is a partial, enlarged section on line 30 of Figure l.

Figures 4 and 5 are partial views, in elevation and plan, of the framelocking device in operative position.

Figure 6 is a partial section on line 0-6 of Fig. 5.

Figure 7 is a diagrammatic front elevation of a modification.

Figure 8 represents two positions of the frame very diagrammatically.

According to the construction illustrated on Figs. 1 to 6, the sheet II,of glass or other material, is suspended by grippers of the frog leg"type, in which the two jaws are provided with sheet engaging points 3and are pivoted at 4 to each other, and at 5 and 6 to the arms of a compass I, so that the whole forms a deformable quadrilateral.

The grippers are suspended by the top of their compass from a support orbar 8 through a resilient device.

In the exemplary embodiment shown each of the precedingly describedgrippers is connected by a rod 9 to a rod 80, terminating at its lowerend in a hook i i and at its upper end in a shoulder formed, forexample, of a Washer I? (Fig. l). The rod i 0 bears through this washer,from above, downwardly on a spring it or other resilient or cushioningmember. This spring it, or similar member, is seated in a tube or casingit and rests on the base I5 in the lower end of said casing. At theupper end the tube or casing it carries a plug it which is connected bymeans of a hook ll to an attaching member it of the support.

As previously stated, by means of the resilient suspension described ormodifications thereof, when the sheet is raised after being heated, theaction of inertia, due to the mass of the plate, is overcome, and thusthe grippers are prevented from suddenly closing and forcing theirpoints 3 into the plate to such depth as to cause local deformation.

The mounting described provides resiliency not only vertically, but alsotorsionally in a horizontal plane, that is, the plate I may turn withincertain limits about a vertical axis without resultant deformation, aswould be the case if the distances ab-a b were invariable and equal. Infact, due to the resilient suspension, the attachments connecting thepoints a, b and a and b may vary in length and follow the geometriclength variations of the distances ab and a b, due to said oscillationsof sheet I, thus preventing the application of the entire force of thegrippers on the sheet.

This second advantage of the resilient suspension is also of importance,the device being completed preferably by a frame intended to prevent orminimize all warping of the plate and at the same time any oscillationof the latter, which would cause inconvenience, as describedhereinafter, at least during the critical period at the beginning of theheating before the tempering.

This rigid frame or chassis I9 is formed, for example, by four tubes I 9braced together pairwise at 20 and connected below by a bar 2| (Figs. 1to 3).

Ailixed to this bar connection 2| are a certain number of guides, whichmay consist, for example, of simple screws 22 oppositely disposed insupports 23, (Figs. 1 to 3).

Without exceeding the scope of the invention, the guides may also beformed of any other similar arrangement, for example, rods carried byscrews, etc. i

The distance between two opposite screws is regulable according to thethickness of the sheets I to be tempered.

Each tube ll! of the frame or chassis l8 may slide in grooves ll (Fig.5) provided in the horizontal frame members of the support 8.

The position of tubes l9 relative to support 8 may be fixed by any kindof retaining device.

For example according to the embodiment represented in Figures 1, 4, 5,6, 7 and 8, the retaining device is formed by grippers 25 provided withhandles 25 and with a retractile spring 26 serving to draw the operatingends of the grippers toward one another. Each member of the grippers 25is mounted for oscillation about a pivot 21 on the bar 8. It is apparentthat through the action of the spring 26 the grippers 25 hold the tubesl9 in the shallow recesses 8 formed in the bar 8. Notches 28 (Fig. 6)are also provided in the tubes at suitable intervals, so that the framemay remain suspended at different heights relative to the bar 8.

The descent of frame l9 after release from the grippers 25 is limited bystops 40 (Fig. 1), which are regulable in position.

The following is the improved method of heating, in accordance with theinvention.

The sheet I of glass, plate, or similar material is first hooked to thegrippers 2, the frame I9 is then carried into a position such that thebottom of the sheet is engaged between the screws 22.

The sheet I thus held by the rigid frame is then lowered into thefurnace to be carried therein to the suitable tempering temperature. Theheating of a glass sheet may be divided into two stages, namely, theinitial heating at lower temperatures, and a subsequent or final heatingI released by manipulating the retaining grippers at higher temperaturesto bring the glass sheet to approximately its softening point. In theinitial heating, distortion of the sheet is apt to occur. In thesubsequent or final heating, whereby the glass sheet is broughtapproximately to its softening point, the tendency to distort or deformno longer exists.

When the temperature of the sheet has reached a certain value, the orderof 450 C. for example, I have found that the tendency of the sheet todeform no longer exists. Thus, when this temperature is attained, theframe is 25, so as to lower it for a degree regulated by the stops 0,and so that the bottom of the sheet is no longer engaged between stops22. This release of the chassis is necessary, because if left in itsinitial position badly tempered zones or nodes would be produced in thesudden cooling by an air jet, these zones being at the point of screws22. It will thus be observed that the subsequent or final heating takesplace without the glass sheet being supported by the chassis frame atits bottom, as shown in Figure 1, or at its bottom and sides, as shownin Figure 7.

On the other hand, notwithstanding that the pressure of the cooling airis exerted on both surfaces in an approximately equal manner, the glassplate oscillates slightly during the cooling, which would bring it incontact with the screws 22 in the form of repeated shocks, which mightmake impressions or imprints in the glass.

It is evident that other means for preventing deformation of the glasssheet in accordance with the invention may be realized, withoutdeparting from the scope thereof; for example, the guides may bedistributed not only over the lower strip of the plate, but over theentire periphery. In such case the sheet is released before thetempering by any suitable mechanism.

Figure 7 shows by way of example a mecha- 7 part of the bar 8 by alocking device 25, of any.

kind, for example, of the type described. To open the chassis l9 so asto free the glass sheet the handles 25 of the gripping device 25 aremoved toward one another, against the action of the retractile spring 26thus removing the grippers from the tubes l9 permitting those tubes tobe moved about the pivot 29 and out of the shallow recesses 8 in the bar8.

When the chassis i9 is thus released it opens under the action of aspring 36, for example, which raises the arms 3| and 32 at 3i and 32'(Fig. 8) and removes the guides from the three edges of the sheet. Theglass sheet is suspended I ing furnace will surround the supportingchassis I and the glass sheet for the necessary heating operation. Thefurnace will be of suflicient dimensions to permit the movement of thechassis frame according to the structures of Figures 1 claim is:

and '7. The top of the furnace or closure is preferably below the casingI4 of the spring suspension means;

It is, of course, to be understood that the in vention is not limited tothe embodiments illustrated and described, which are given by way ofexample only.

Having thus described my invention, what I l. The method of supporting asheet of glass for heating preliminary to tempering which consists insupporting thesheet from above and restraining the sheet against lateralmovement during the initial heating and through the temperature range atwhich the sheet has a tendency ment from the sheet upon the increase intemperature thereof above the range of distortion.

I GEORGES PAUL DESPRET.

